I JUST BOUGHT A 69 ELCO WITH POWERGLIDE 2-SPEED TRANNY BEHIND A 350.WOULD A TH350 BOLT UP TO MY CROSSMEMBER OR WOULD I HAVE TO CHANGE THAT OUT TOO? ALSO DO YOU THINK A TH350 WOULD BE ABLE TO WITHSTAND A 350-400 HP MOTOR. I WOULD NOT BE DRIVING ON THE HIGHWAY MUCH SO MAYBE I CAN GET BY WITHOUT ONE OF THOSE EXPENSIVE OVERDRIVE UNITS. THANKS!!

I JUST BOUGHT A 69 ELCO WITH POWERGLIDE 2-SPEED TRANNY BEHIND A 350.WOULD A TH350 BOLT UP TO MY CROSSMEMBER OR WOULD I HAVE TO CHANGE THAT OUT TOO? ALSO DO YOU THINK A TH350 WOULD BE ABLE TO WITHSTAND A 350-400 HP MOTOR. I WOULD NOT BE DRIVING ON THE HIGHWAY MUCH SO MAYBE I CAN GET BY WITHOUT ONE OF THOSE EXPENSIVE OVERDRIVE UNITS. THANKS!!

I don't like a THM 350 as a rule.... But if you are only putting it to about 350 to 400 (limit) then it will probably last for a time. Get rid of any 2.73:1 rear end gears and go with a 3 something. 3.42:1 is good and about max if you like being able to hear the radio on the highway. I would guess that you have a GM 10 Bolt about a 8.5" ring gear, but that is just a guess. If its true then that is plenty of rear end to deal with up to 500 Horses easy, with new gears from a good manufacturer. No *** stuff or things like Jeg's brands. Generic gears are tired and inconsistant.

Good Luck.

The TH350 will bolt right in, the only thing you have to deal with is the shift indicator on the dash and the cooler lines.